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|Factorization||2 × 11|
|Divisors||1, 2, 11, 22|
- 22 is a deficient number.
- 22 is an even composite number and a semiprime; its proper divisors are 1, 2, and 11.
- 22 is a pentagonal number and a centered heptagonal number.
- When cutting a circle with just six line segments, the maximum number of pieces that can be so created is 22, thus 22 is a central polygonal number (see lazy caterer's sequence).
- 22 is the sum of the totient function for the first eight integers.
- 22 is a Perrin number, preceded in the sequence by 10, 12, and 17.
- 22 divided by 7 approximates the irrational number π, the ratio of the circumference of a circle to its diameter.
- 22 is an Erdős–Woods number, since it is possible to find sequences of 22 consecutive integers such that each inner member shares a factor with either the first or the last member.
- 22 is a Smith number in base 10.
- "2-2" is the only fixed point of John Conway's look-and-say function.[importance?]
In physics and chemistry
- 22 is the designation of the USAF stealth fighter, the F-22 Raptor.
In art, entertainment, and media
- "Twenty Two" is a 1997 song by the punk band Millencolin
- In Jay-Z's song "22 Two's", he rhymes the words: too, to, and two, 22 times in the first verse.
- "22 Acacia Avenue" is a song by Iron Maiden on the album The Number of the Beast
- Catch 22 is an album by death metal band Hypocrisy
- "22" is a song by Lily Allen on the album It's Not Me, It's You.
- 22 Dreams is a song and album by Paul Weller. The album contains 22 songs on it.
- The Norwegian electronica project Ugress uses 22 as a recurring theme. All four albums feature a track with 22 in the title.
- "22" is a song by Taylor Swift on her fourth album Red
- "The Number 22" is a song by Ashbury Heights on the album The Looking Glass Society.
- 22, A Million is an album by Bon Iver. The first track of the album is called "22 (OVER SOON)".
- Cubic 22 was a Belgian techno duo.
- "22" is a song by the English alternative rock band Deaf Havana on their album Old Souls
In other fields
- Catch-22 (1961), Joseph Heller's novel, and its 1970 film adaptation gave rise to the expression of logic "catch-22".
- Revista 22 is a magazine published in Romania.
- There are 22 stars in the Paramount Pictures logo.
- "Twenty Two" (February 10, 1961) is Season 2–episode 17 (February 10, 1961) of the 1959-64 TV series The Twilight Zone, in which a hospitalized dancer has nightmares about a sinister nurse inviting her to Room 22, the hospital morgue.
- Traditional Tarot decks have 22 cards with allegorical subjects. These serve as trump cards in the game. The Fool is usually a kind of wild-card among the trumps and unnumbered, so the highest trump is numbered 21. Occult Tarot decks usually have 22 similar cards which are called Major Arcana by fortune-tellers. Occultists have related this number to the 22 letters of the Hebrew alphabet and the 22 paths in the Kabbalistic Tree of Life.
In computing and technology
- 22 is the standard port number for the Secure Shell protocol
- A quotation mark (in a URL it appears as a "%22")
- There are 22 letters in the Hebrew alphabet.
- In the Kabbalah, there are 22 paths between the Sephirot.
- In soccer there are 22 players that start a game and the maximum number of players playing at any time.
- In Australian rules football, each team is allowed a squad of 22 players (18 on the field and 4 interchanges).
- The length of a cricket pitch is 22 yards.
- In rugby union, the "22" is a line in each half of the field which is 22 meters from the respective try line. It has significance in a number of laws particularly relating to kicking the ball away.
In weights and measures
In other uses
Twenty-two may also refer to:
- 22 is the number of the French department Côtes-d'Armor
- "22" is a common name for the .22 calibre .22 Long Rifle cartridge.
- In French jargon, "22" is used as a phrase to warn of the coming of the police (typically "22, v'là les flics !" (In English: "5-0! Cops!")
- In photography, f/22 is the largest f-stop (and thus smallest aperture) available on most lenses made for single-lens reflex cameras
- Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1986): 31
- Sloane, N. J. A. (ed.). "Sequence A000124 (Central polygonal numbers (the Lazy Caterer's sequence))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Sloane, N. J. A. (ed.). "Sequence A002088 (Sum of totient function)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Sloane, N. J. A. (ed.). "Sequence A001608 (Perrin sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Sloane, N. J. A. (ed.). "Sequence A059756 (Erdős-Woods numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
- Martin, Oscar (2006). "Look-and-Say Biochemistry: Exponential RNA and Multistranded DNA" (PDF). American Mathematical Monthly. Mathematical association of America. 113 (4): 289–307. doi:10.2307/27641915. ISSN 0002-9890. Archived from the original (PDF) on 2006-12-24. Retrieved 2018-11-21.
|Wikimedia Commons has media related to 22 (number).|
- "The Number 22 at The Database of Number Correlations". Virtuescience.